I had problem with SDK and other options but with FSUIPC I solved like this: a macro for FSUIPC, and then in the simulator select them as needed.

Here is the macro that has to be saved with name you decide and called in the ini.

1.1=C70087, -2147483648
2.1=C74184, 536870912
2.2=C74184, 131072
3.1=C70087, 536870912

In the simulator click your hardware up and select in Add Ons FSUIPC then under Button + Switches:
Control when sent: NGX_GEAR_up
parameter 1
Control sent when button released: ngx_gear_down
Parameter 1


Should work, Luis